Aspen doctors find precision with robotic arm

Using an instrument attached to a robotic arm, Dr. Thomas Pevny, left, performs a partial knee replacement on a patient at Aspen Valley Hospital. The computer screen displays in green the area of the bone to be cut away.

Janet Urquhart/The Aspen Times

Using an instrument attached to a robotic arm, Dr. Thomas Pevny, left, performs a partial knee replacement on a patient at Aspen Valley Hospital. The computer screen displays in green the area of the bone to be cut away.

ASPEN (AP) – Orthopedic surgeons at Aspen Valley Hospital have teamed with a new player in the operating room, one that’s making them better at what they do.

The hospital is one of two in Colorado to offer MAKOplasty, a procedure that employs a robotic arm to assist surgeons in performing hip and partial knee replacements.

Or, as Dr. Tomas Pevny of Aspen Orthopaedic Associates suggested, perhaps the surgeons are assisting the robot. Either way, local surgeons say the robotic tool has increased the accuracy of the procedures, made the surgeries less invasive and sometimes made partial knee replacements possible when a total knee replacement was previously the only option.

“I don’t get excited about much in orthopedics, but this is very cool,” said Dr. LeeLee von Stade, also a surgeon with Aspen Orthopaedics.

The $1.25 million system was installed in August, purchased with the hospital’s capital funds. The hospital anticipates 60 MAKOplasty cases per year and has seen about 20 operations make use of the equipment so far, according to Ginny Dyche, community relations director at the hospital.

“With only two in the state (the other is in Denver), we do anticipate we’ll be getting patients from outlying areas,” she said.

The technology allows the creation of a virtual, three-dimensional image of a patient’s joint, with the replacement parts inserted, before the surgeon sets foot in the operating room.

“Even before surgery, I know what size components I’m putting in and where I’m going to put them,” Pevny explained before performing a partial knee replacement on a Carbondale man last week.

Not only does the technology sometimes make a partial knee replacement possible when a total replacement was previously necessary, it takes some guesswork out of the operation, according to Pevny.

The partial surgery leaves all the knee ligaments in place, which is good because the joint retains its natural movement. However, placing the components for a partial knee replacement previously required a degree of subjectivity on the surgeon’s part, and if the positioning wasn’t perfect, an eventual loosening and failure could result, Pevny said.

MAKOplasty allows a surgeon to place the implants precisely in the joint. In the operating room, the patient’s knee is synchronized to a three-dimensional scan of the joint, displayed on a computer screen, and the surgeon wields a tool connected to a robotic arm to make the necessary cuts to the bone to accommodate the implants. As bone is carved away, the image on a computer screen suspended above the operating table displays the progress.

The system is not unlike Nintendo Wii video-game technology, which detects the three-dimensional movements of a player grasping a hand-held controller and translates them to the image on a television screen.

“The robot, when we decide that’s where we want to cut the bone, does it precisely every time,” Pevny said. “It takes the subjectivity out of it.”

The robotic arm won’t let the surgeon make a cut beyond the pre-established parameters. The tool shuts down before the surgeon can stray outside the borders with the cutting tool (a high-speed, rotating instrument called a bur).

“A lot of patients have the wrong idea – that it’s a robot doing surgery. It’s really a guidance system,” said Dr. Lindsay Harris of Aspen Orthopaedics, who also has been trained in MAKOplasty.

While the surgeon joins forces with the robotic arm, a specialist who works for MAKO Surgical Corp. hovers over a computer keyboard in the operating room. The specialist oversees the software end of the technology, creating the three-dimensional image using a scan of the patient’s joint and synchronizing the components of the system.

While von Stade and Pevny are using the technology for partial knee replacements (it isn’t used for total replacements), Harris is using the system for hip replacements.

Aspen sees its share of knee injuries because of a generally active local populace coupled with downhill skiing in particular. Knee surgeries of all types last year at Aspen Valley Hospital totaled 449; there were 476 cases in 2012 with about a week left in the year. Hip replacements, according to Harris, are less frequent, but MAKOplasty should make patients more comfortable with having the procedure here rather than traveling to Denver, where surgeons perform a lot more of them.

The accuracy of a hip replacement, as with the partial knee replacement, is improved with the robotics, Harris said.

“I tell you, when I use the robotic system, the way we put it in before the case starts is the way it looks afterward in the X-ray,” he said. “It’s not foolproof, but it’s pretty close.”

For Jodie Bay, a former longtime resident of Woody Creek who now calls Silt home, the accuracy of the procedures lured her to the Aspen hospital for a hip replacement in October and a knee operation in early December despite the long drive between Silt and Aspen for follow-up care.

Her goal is to be riding horses again by June, and so far, Bay said she is pleased with her recovery.

“I’m really surprised by how good I’m feeling and how mobile I am,” she said.

While the cost of a knee or hip procedure involving MAKOplasty at Aspen Valley Hospital is exactly what it was without the system, some patients are spending fewer nights in the hospital afterward, which translates into lower costs. And recovery time seems to be improved, von Stade noted.

Bay said her physical therapists have been amazed by her progress to date.

“They’re just like, ‘Wow, I can’t believe how fast you’re progressing,’” she said.